1. Field of the Invention
The present invention relates to inclined approach ramps for automotive support platforms, and particularly to ramps for vertically movable support platforms, such as drive-on wheel alignment platforms of the type used in automotive service stations and the like.
2. Description of the Prior Art
Automotive service stations, garages and the like typically have vehicle platforms for supporting an automotive vehicle for the performance of various service functions thereon. The platform, which may comprise a pair of transversely spaced-apart runways, is typically elevated or elevatable so as to facilitate access to the underside of the vehicle. In the case of an elevated platform, an access or approach ramp must be provided to permit the vehicle to be driven onto the platform. Even in the case of lift-type platform which is movable vertically between raised and lowered positions, in the lowered access position, the platform is still typically spaced above the floor of the garage so as to accommodate the lifting mechanism, so that an approach ramp must also be used in this case. One such type of elevatable platform is a wheel alignment platform, which carries apparatus specifically designed for use in performing wheel and front end alignment functions on the vehicle.
Heretofore, such automotive service platforms have utilized approach ramps which define an inclined plane, disposed at a single predetermined angle to the garage floor. The angle must be shallow enough to prevent the underside of the the vehicle from contacting the ramp or the horizontal platform, and yet steep enough so that the overall length of the ramp will be short enough to fit within the dimensions of the garage.
Many newer styles of automobiles have low-slung chassis providing a minimal clearance between the bottom of the chassis and the roadway. For example, many vehicles have at the front end of the chassis a depending "air dam" for aerodynamic purposes, which provides very little ground clearance. When such vehicles are driven onto the existing approach ramps for automotive service platforms, such as wheel alignment platforms, the "air dam" or some other part of the chassis frequently strikes the ramp before the front wheels of the vehicle contact the ramp, resulting in damage to the vehicle. This can be avoided by providing an approach ramp at a shallower angle, but it has been found that when the ramp angle is made small enough to avoid contact with low-slung vehicle chassis, the length of the ramp becomes such that it may extend beyond the limits of the garage floor so that the garage door cannot be closed.